Receiver



'Unirse STATES PATENT, OFFICE.

HENRY C. HARRISON, OF NE'W YORK, N. Y., ASSIGNOR TU VESTERN ELECTRICGGMPANY, INCORPORATED, 0F YORK.

NEW' YORK, N. Y., A CORPRATION OF 'NEW RECEIV ER.

Application filed October 23, 1918.

To all wfiomz't may concern.' A

Be it known that l, HHNRY (l. Hannisou. a.- citizen of' the UnitedStates, residing at New York, in. the `county oi N ew York, State ot"kNew York, have invented certain new and useful llnproveinents inReceivers. of which the following a full, clear, conoise, and'exactdescription.

This invention relates to telephone .rev ceivers'for `general use intelephone or signailing circuits and has for its object Yto provide areceiver with an improved magnetic structure and one having its partsso' pro-- portioned and arranged as to provide aninstruinent of highsensitivity in responding to the feeble alternating currents such as'those vgenerated hy voice waves impinging.

npon the diaphragm of a telephone transvv'mitten vMore specifically, theobject of this invention is to provide a telephone receiver having itsmagnetic structure so arranged as to provide a path of low reluctancefor the flux nenerated bythe alternatingv or voice currents andtherefore capable of operating' elliciently and without causing unduedistortion in the voice current wave forros.

To attain this object, the invention consists oi? certain new and novelfeatures in the construction as will he more fully described andparticularly,pointed out in the appended claims.

ln the accoinpanying;r drawings. Figure 1 is an enlarged view inperspective oi' the magnetic structure of the receiver embodying' this`invention: Fig. 2 is an inverted plan view pai-tl)y in section of thereceiver shown in lfig. 1; and Fig. fis a diagrammatic View of theinagrnetie circuit of receiver shown in Fig. 1.

lietcrringI now to the drawing, there is shown the magneti(- ol thecustomary wateh-case tjvpe. The permanent magnet 5 which issemi-circular in shape is provided at its ends with inwardly andupwardly etei'nlingY polar extensions 6 and i which are secured in placehv means ol' the screws 898. rl'he iree ends ofjmemhers 6 and 7 aretriton-.ated to provide two sets ol" pole pieces 9. 'l0 and ll. and l2.'i3 and 14. The outer pole pieces il. ll. IQ and 'lflare lientoutwardl)7 and i'ormed to lie in a. circle. rPhe inner pole pieces l()and 13 are heut inwardlv and provided with enero'izing ywindings iii andlli. respectively.

Specification of Letters Patent.

.Securely fastened to circuits.

structure oi ay receiver "Patented sept. 14., 1920. serial No. 259,365.

the receiver diaphragm 17 a cup-shaped magnetic member 18, the wall 19of which lies outside of the polepieces l0 and 13 but inside of the polepieces 9, 11, 12 and 14. The 'talking windings 15 and 16 are connectedin series and in such a manner that current iowing through the windingsin a given direction will ineke the o oles 10 and 13 of oppositepolarity. This' is represented in Figi-lof the drawingji1 by markingpole 10A with a H9 sign4 and pole 13 with a sign as showing thedirection of flux at a given instant resultingr from voice currentstraversing the windings in the direction indicated by the small arrows.

With current Flowing through the windings in the direction asdesignated, the operation of the receiver will he leasily un# derstoodby an examination of the magnetic The main path for the. polarizing fluxis from pole l() across the air-gap to cup memberlS, thence across theair-gap'to pole piece 13 and back to pole 10 through polar extension 7,magnet 5 and polar extension 6. Parallel paths are also providedtrompoles 9 and 1l to the Wall portion 19 and from the wall portion 19to poles 12 and 14.. Since the direction of flux across ,the air-gaps inthese paths is radial there is no force exerted tending1 to causemovement ot' the' receiver diaphragm. l

The paths tor the ythis generated by voice currents flowingu through thetalkingq windings 15 and 1G with the direction of current as'indicatedare as follows: V 'd (1) From pole 1.0 across the air `gap tocopmeinher18. to wall portion 19, thence across the air-,gaps in and hack to pole10.

(2) From pole piece 13 to polepieces 12 and- 14, thence across theair-zaps in parallel to the wall portion 19. cup-member 18 and acrossthe air-gap to pole. 13.

(E) From pole piece 10 across the airgap to cup-member '18, across theair-grap to pole 13, through polar extension?, perinanent inagi'iet 5and polar .extension 6baclr to pole l0. I

The reluctance of the. latter path, however, is so high to alternatingcurrents of voice frequencv that the flux will tend tov leak acrosshetween the polar extensions rather than to pass through the permanentmagnet. With the above paths for the p olarizing' flux resulting" fromthe permanent fis parallel to poles 9 and 1l magnet and the alternatingHux generated by the voice currents at a given instant, it

will be noted that the flux from the talking winding is in a directiontoaugment the polarizing flux passing from pole 10 to cupmember 18 andfrom the cup-member to pole 13, thus increasing the pull on thediaphragm 17. The" flux from the talking winding passing from the wallportion 19 otl ciip-member 18 to poles 12 and 14 wall portion 19 is in:tore does not affect the pull on the diaphragm. With the currentflowing through the talking windings in the opposite direction, the fluxfrom the talking windings is in a direction to oppose the polarizingflux passing across the air-gaps from the pole 10 to the cup-member 18and from thel cup-member to pole 13. The flux from the talking windingspassing from poles 9 and 11 to the wall portion 19, to cup-member 18 andfrom the wall portion 19 to poles 12 and 1-1 is in a radial direction asin the revious case, and, therefore, does not a ect the pull on thediaphragm 17.

The outer poles 9, 11, 12 and 1-1 in combination with the wall portion19 of` cup- "memberq18, provide low reluctance return .paths for thealternating currents.

Because of the relatively large air-gaps existing between poles 9, '11,12- and 111, and the diaphragm 17, the latter, if of magnetic materialis not affected appreciably by Pflux passing through these poles.However, in this design it is not essential that the diaphragm itself beof magnetic material, since the cup-member can be proportioned tosatisfactorily carry the flux generated. Because of the low reluctancepaths provided for the alternating current flux generated by the voicecurrents the magnetic struc-.

ture embodying this invention provides a receiver of high sensitiveness.A further advantage o'the low reluctance return paths for the alternatecurrent iiux isthe .lesser tendency for the receiver to be demagnetized.

What is claimed is: 1. Atelephone receiver comprising a per manentmagnet, a pair of triturcated polar extensions secured to the endsthereof, a. magnetizing winding for each of said polar extensions, andadiaphragm in operative relation with the 'middle trifurcations of saidvpolarextensions, but so disposed with respect to the outer trifurcationsof said polar extensions -as not to be eii'ect'ed by inagnetic fluxpassing therethrough. d

2. A telephone receiver comprising a permanent magnet, a polar extensionsecured to the magnet at each end. the free end of each polar extensionbeing formed to pro vide three pole pieces. a maguetizing winding on themiddle pole piece of each extension, and a diaphragm in operativerelation a radial direction and there` with said middle pole pieces butso .disposed with respect to said other pole pieces as not to beaffected by magnetic flux passing therethrough.

3. A telephone receiver comprising a permanent magnet, a pair ofinwardly extending polar extensions secured thereto," lthe free end ofeach polar extension being formed to provide three pole pieces, amagnetizing winding on the middle pole piece of each extension, saidwindings being connected inhseries, and a diaphragm in operativerelation with the middle pole piecesof said polar extensions, but sodisposed with respect to said other pole pieces as not to be aifected bymagnetic flux passing therethrough.

4. A telephone receiver comprising a permanent magnet, a trifureatedpolar extension so formedfas to provide three pole pieces secured toeach end of said magnet, the middle pole piece of each extension beingJformed to lie inside of the outer pole pieces, a diaphragm, and amagnetic cupshaped member secured to the diaphragm and in operativerelation with said pole pieces. u

5. A telephone receiver comprising a semi-circular permanent magnet, apolar extension secured to each end of the magnet, the free end of eachof said polar extensions being formed to provide three pole pieces outof line with each other, a magnetizing windingsecured on the middle polepiece of Y establishing a. constant magnetic potential between saidpolar extensions, means for establishing varying magnetic potentialsbetween said polar extensions, yand a diaphragm in operative relation tothe middle trifurcations of said polar extensions, but so v disposed asnot to be affected by the magnetic flux passing through the outertrifurcations of the polar extensions.

7. A telephone receiver comprising a plurality of pole pieces having amagnetizing winding thereon, a diaphragm in operative relation to saidpole pieces, means for impressing a constant magnetomotive force on saidpole pieces. means for impressing a variable magnetomotive `force onsaid pole pieces` and a plurality ot' additional pole pieces adapted toprovide ,return paths for the flux generated by said magnetizingwindings and so disposed." as to exert no pull upon said diaphragm.

8. A telephone receiver comprising a plu-- rality of pole pieces havinga magnetizing Winding thereon, s diaphragm having a variableinagnetomotive force on said pole pieces, :ind n plurality ci'additional pole' pieces adapted to provide return paths for the tlizxgenerated by said megnetixing windings but so disposed :is to exert nopuii upon sziid diaphragm.

9. telephone receiver comprising relitji7 of pole pieces having :irnngnetizing winding thereon, means for impressing e constantmagnetomotive'forciy on seid pole pieces, means for impressing :ivariable magnetomotive force on said pole pieces, a plurality ofadditional pole pieces adapted to provide return paths forthe flux gene:i pilirated by said magnetizing windings u dia- 4 phrzigm, and amagnetic cup-shape member attached to the diaphragm, said cupsho-pedmember including a Well portion extending between said .first polepieces and said Second pole pieces.

l0. A telephone receiver comprising a plurniity oi' pole pieces having amagnetizing winding thereon, means for impressing a constantnnignetoniotivc torce on said pole pieces, menns'for impressing uvariable magnetomotive force on seid pole pieces, rality of additionalprovide return paths :i plupole pieces adapted to for the ux generatedby said mzignetizing windings, :i diuph mgm,

and, magnetic cup-shaped member atL taehed to the diaphragm, saidcup-shaped member being provided with rightengle portions extendingbetween said first pole pieces and said second-pole pieces to provide ereturn path for alternating current flux in a direction which does notexert any pull upon the diaphragm,

In Witness whereof I hereunto subscribe my name this 18th day ofOctober. AqD; l

HENRY C. HARRISON.

